Transportation Glossary

The following is a listing of transportation-related terminology and phraseology developed by CCMPO.
Click here to view a list of Acronyms only...

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Term	Acronym	Definition
Off Peak		Trips that occur during period of relatively low traffic.
Official Business Directional Sign	OBDS	An official Vermont Agency of Transportation designated business directional sign, which includes a legal business name, logo, directional arrow, and mileage from the business. Black OBDS signs indicate businesses, where brown OBDS signs represent recreational areas (brown signs requiring FHWA approval to use). Towns are assessed an installation fee and an annual maintenance fee for each sign.
Offtracking		The tendency for rear tires to follow a shorter path than the front tires when turning. This is a primary concern with Trucks, Buses, or trailered vehicles because rear tires may clip street signs, or drive onto shoulders, walkways, or bike lanes, or cross the centerline on a curve, creating a safety hazard for adjacent and oncoming traffic.
Origin		The location or zone at which a trip begins; the place where a trip is “produced.”
Origin/Destination Study	O-D	A study of where person or vehicle trips begin and end. Such a study may also include trip purposes and frequencies.
Ozone	O3	A colorless gas with a sweet odor that is not a direct emission from transportation sources, but is formed when VOCs and NOx from car exhausts and some industrial emissions combine in the presence of sunlight. Ground-level ozone is associated with smog conditions and initiates damage to lungs, trees, crops and materials. Requlated by the Clean Air Act Amendments of 1990 (CAAA).

OTHER TRANSPORT TERMINOLOGY REFERENCES: